Telecommunications service providers and equipment manufacturers are now rapidly developing and deploying packet-switched data communication networks that can carry voice and telephone call information, and that conform to published, non-proprietary engineering standards and protocols. Such “open packet telephony” (“OPT”) networks allow for integrating multiple services, such as voice and data, on the same network, which results in a cost savings.
One class of OPT networks is based on ITU recommendation H.323. Other OPT networks may be based on Media Gateway Control Protocol (MGCP) and its derivatives, such as SGCP, MeGaCo, H.248, and Session Initiation Protocol (SIP). In OPT networks based on the H.323 family of protocols, more intelligence is placed in the network as opposed to controllers. In contrast, OPT networks based on MGCP and similar protocols are designed such that individual networking devices store and process limited information about the network and its protocols (“intelligence”) and hence place most of the intelligence that is required for voice services in gateway controllers.
Generally, in an OPT network, voice functionality is separated into different planes. A bearer plane and a switching plane communicate data packets between endpoints. Media Gateway (“MG”) devices are located at the edge of the packet network and interface the packet network to other networks, such as the public switched telephony network. MGs provide facilities to transmit and receive data over the packet network, and convert data between the Time Division Multiplexed (TDM) format that is used in telephony networks, and the packetized voice payload format that is used in OPT networks. The signaling and control plane provides call intelligence, processing signaling, routing calls, interpreting dial plans, etc.
The signaling and control plane comprises one or more Media Gateway Controller (MGC) devices. MGCs instruct MGs through a control protocol such as MGCP to create, delete and modify voice connections. MGCs also terminate the signaling required for voice. In cases where signaling is physically connected to a Media Gateway, as with Primary Rate Interface or PRI, the signaling is backhauled between the MG and MGC. In this context, a “backhauled” signal is one that is transported from a MG to a MGC, because the MGC is the entity that possesses or controls the MG.
Although OPT networks provide cost savings, managing OPT networks is far more complex than managing the TDM switches that are found in conventional circuit-switched networks, which the OPT networks are replacing. With TDM switches, operators manage and interact with fewer devices, possibly even one device, although each device is complex. In contrast, operators of OPT networks are required to manage and interact with a significant number of devices and many different types of devices. In short, where operators previously had to manage one network element, operators now have to manage an entire network.
For example, configuration and provisioning of the devices in an OPT network must be coordinated. Configuration mismatches must be properly detected. Alarms between different devices must be correlated where different devices detect the same error condition and, therefore, generate redundant alarms. As a further complication, the common principles underlying the operation of the OPT network are often not well understood by operators, who tend to “think” in terms of boxes rather than in terms of general architecture. This increases costs and reduces profitability of service providers, as general operational complexity is increasing.
Further, how network management applications handle a problem is largely determined by how the application domain is modeled through data structures, program functions, and related processes. There is a need for modeling OPT networks in a way that simplifies dealing with such networks while addressing the unique properties of an OPT network. Current protocols and standards fail to address this need. In current approaches, network elements that represent MGs and MGCs are simply modeled and managed like any other network elements.
Distribution of functionality is one problem. Whereas TDM networks traditionally comprise monolithic network elements that hide much of their internal complexity, some of this complexity is now exposed, as functionality is distributed over several independent and cooperating components. Each component on its own is significantly simpler than a TDM switch, but the overall complexity of the network is higher, and it has a greater number and variety of components. Consistent provisioning of control elements as well as provided services can be a challenge because there is often a need to correctly configure multiple network elements.
Openness also results in management difficulty. Different components now provide functions that formerly were provided by the same TDM switch, and the different components may come from different vendors and may comprise different equipment types. There is a need for a way to accommodate future releases and implementations of MGs in a network management solution.
Flexibility also causes management challenges. Networks can have vastly different architectures. Central office equipment and customer premises equipment with different characteristics all may participate as MGs in the same virtual switch. The relationship between MGs and MGCs may vary over time.
Integration causes still other problems. A bearer network may carry services other than voice, which require management. A component acting as MG in a voice network may at the same time be part of a traditional data network. This introduces overlaps and dependencies between management domains, introducing additional complexity.
H.323 networks share similar problems. Indeed, in H.323 networks, the management problems outlined above can be considered even more acute because intelligence is less centralized than in an MGCP network. Based on the foregoing, there is a clear need in this field for improved methods to manage OPT networks and devices in them.
There is a particular need for an integrated network management solution for OPT networks that use ITU Recommendation H.323, so that gatekeepers and gateways are managed in a coordinated way.
There is also a need for a way for a solution that is operable in a way that is intuitive for an administrator or operator.